1. Field of the Invention
This invention relates to refuse collection compactors for use on refuse or recycling vehicles and to refuse collection compactors used to compact plastic containers or the like while on a refuse recycling vehicle.
2. Description of the Related Art
More and more communities are beginning to recycle plastic and particularly plastic containers because landfill sites are being filled and because the plastic is not readily biodegradable and lasts in these landfills for many years. Such communities are having their refuse segregated at the pick-up site into paper, glass and plastic categories; and have refuse trucks with three or more segregated units or compartments each assigned to hold a specific category of refuse. The plastic compartment or unit is providing a problem in that it readily fills with hollow plastic containers, often plastic blow-molded containers for quarts, half-gallons, or gallons of liquid such as milk, etc. It has been recognized that a compaction of the plastic containers could reduce volume needed for plastic by a factor of 6 to 1 or even 10 to 1, thus allowing trucks to pick up more refuse before unloading.
An attempt to provide a commercially acceptable plastic container compactor mounted on a refuse truck employed a pair of rams in a compaction chamber, each ram being mounted for movement at right angles to the other. A plastic bottle is inserted into the compaction chamber, and a first ram crushes the bottle. The second ram thereafter pushes the crushed bottle into a discharge chamber and may apply additional compaction thereto during the process. However, only a single plastic bottle can be accommodated at any one time and such is unsatisfactory for waste collection situations in that it is too time consuming to wait for a single container to be compacted. A typical residence may produce a half dozen plastic containers or more during a collection cycle, and larger waste collection customers such as hospitals, restaurants and commercial establishments produce plastic containers in much greater quantities. Hence, it is impractical to process such plastic containers, one item at a time.
The space on a recycling truck for such materials is quite limited. Usually the truck beds are only eight feet in width; and while considerably longer in length, the length is usually divided into a plurality of separate compartments for containers for glass, paper, and plastic. The usual space allotted for a compactor for one compartment will be typical in the range of three to four feet. The height of the compartment having the compactor is also limited and is usually about three to four feet in height above the truck bed. Thus, the space available for an onboard compactor unit and the storage volume for the compacted material is relatively small. Further, it is desirable that the incoming materials being put into the compactor through access openings on either side of the truck so that the driver need not go around the truck irrespective of which side of the truck the driver is on. The access from either side further reduces the actual volume left for the compacting apparatus and for holding compacted materials. The use of a pair of rams mounted at right angles to one another uses a considerable volume within the container leaving a minimal volume for the compaction chamber in which the compacted materials are stored.
In a compactor unit having a ram, the ram and its fluid actuating cylinder or cylinders occupy a considerable volume and this is not problem where the unit is stationary and/or has a large space in which to be situated and can have a large (often separable) receiving chamber for storing the compacted refuse. The problems facing a design for such refuse vehicles is that there is a very limited volume space on a truck for each collection unit; and in particular, for the plastic compactor unit because of the space needed for the operating strokes of the ram and its operating mechanism. In the eight foot truck bed width, for example, it is desirable to have a receiving chamber capacity of at least five feet and to have the ram penetrate into the compaction chamber at least six inches (preferably seven inches or more) so that the compacted material will not spring back into the receiving opening in front of the ram when the ram returns to its retracted position. Preferably, the opening to receive a quantity of plastic in front of the ram space is relatively large, for instance, twenty inches or larger. This leaves only about eighteen inches left in the eight feet width for the ram and its operating cylinder.
Preferably, the ram ought to have a stroke of over twenty-six inches to move across the opening and at least six inches into the receiving chamber. This is a somewhat paradoxical requirement of having only eighteen inches for a ram and its cylinders and yet expecting a twenty-seven inch or more stroke. It is not only a length problem to be solved, but is also a volume problem in that it is preferred that the person throw in the plastic containers from either side of the vehicle in over the tops of the receiving chamber and over the top of the compaction chamber in which is positioned the ram apparatus, from each side of the truck. Thus, there must be a volume used in the unit as an inlet chute preferably in the upper portion of the unit for directing the containers to a position in front of the ram. Typical, loading heights are two feet to four feet above the truck bed. By way of example only, the volume occupied by the ram apparatus in a compactor having an eight-foot width, a height of three feet and a depth of three feet should be preferably about 0.25 cubic yard or less with a receiving container capacity of 1.00 cubic yard. In larger units, having a four-foot height and a depth of four feet with an eight foot across the truck width, the ram apparatus may be about 0.37 cubic yard and the receiving container may have a 2.00 cubic yard capacity with a longer ram stroke of thirty-nine inches or longer. Manifestly, the dimensions are by way of example to indicate the severity of the engineering problems to accommodate all of these requirements in a very small space. By way of example, the forces desired are quite large for compaction with a preferred ram face pressure in the range of 1,600 to 2,200 psi to achieve packing forces in the range of 22,600 to 55,400 pounds. These forces are typical and representative and may be changed, as desired, to meet different criteria.
In addition to receiving compacted containers, there is also the problems of discharging and segregating the compacted plastic. Herein, there is an easily open door discharge which allows the containers to be dumped onto a segregation area or conveyor so that the plastic may be segregated as to type. If one shreds the plastic while on board the truck, it is more difficult to segregate and classify as to material type. It appears that typical plastic refuse may be as follows:
______________________________________ LDPE: Garbage Bags, Bread Wrappers 40% HDPE: Milk and Detergent Bottles 28% Polypropylene: Lids and Heavy Wrappers 10% Polystyrene: "Clamshells" 10% PET: Soft Drink Containers 7% PVC: Cooking Oil Containers, Food 4% Wrappers ______________________________________
The present invention will dump such a typical refuse on a sorting area or a conveyor for further segregation of each of the above plastic materials.
Because the compactor is mounted on a truck, it needs to be small but also it should be relatively lightweight to travel over city streets and country roads. By way of example, the above-described compactors of this invention weigh between 1,820 and 2,480 pounds. Compactors are also subjected to abuse and they should be relatively trouble-free. Safety in loading, compacting and discharging of the compacted material are also criteria to a successful traveling, vehicle compactor on a recycling truck. Also, discharge of the compacted material from the compaction chamber should be a quick and easy task, preferably using the compaction ram to push the compacted material from the compaction chamber and/or the compactor should be easily titled for gravity and sliding unloading.